The present invention relates generally to an apparatus for heat-treating wood and, in particular, an apparatus and system for disinfesting a large number of wood products by raising the temperature of the wood products to a specified temperature for a specified period of time.
A primary method of treating wood and wood products in order to remove pests was fumigation. The fumigation process consisted of placing the wood products in an enclosed volume and flooding the volume with a hazardous airborne chemical capable of killing pests. The most commonly used chemical to fumigate such wood products is methyl bromide. These fumigation techniques have the potential of endangering human operators who worked nearby and polluting the environment.
The European Union (EU) has decided to prevent the introduction of the pests into the European continent. In order to achieve this goal, the EU has adopted measures requiring the treatment of all wood and wood products including non-manufactured wood packaging (NMWP).
The recently adopted measures by the European Union allow three treatment options for NMWP, namely, heat treatment, fumigation, or chemical pressure impregnation. Although, the EU measures do not call for a specific chemical for use in fumigation or chemical pressure impregnation, individual EU countries may ban the importation of NMWP that have been treated with specific chemicals.
The International Plant Protection Convention has adopted an international standard very similar to those of the European Union that applies to all NMWP, coniferous and hardwood. (The International Plant Protection Convention is recognized by the World Trade Organization as the official international plant protection organization.) The standard currently lists heat treatment as the only xe2x80x9clong term measurexe2x80x9d to destroy the pests in wood.
The heat treatment measure is less dangerous to workers conducting the treatment and safer for the environment when compared to fumigation or chemical pressure impregnation treatments. Also, in the United States, the Environmental Protection Agency (EPA) is responsible for registering and establishing technical specifications for pesticides. All fumigants are restricted-use pesticides and they may only be purchased and applied by licensed commercial pesticide applicators. Although it is a violation of Federal law for commercial applicators to apply a pesticide in a manner inconsistent with the EPA label, it is the State, not the Federal government, that licenses commercial applicators.
Environmental concerns also arise in connection with the large-scale use of pressure-impregnated wood. For example, the Netherlands has recently prohibited the commercial importation of wood impregnated with copper compounds because of environmental issues. Like fumigants, pressure impregnation chemicals are regulated by the EPA and may only be used by commercial applicators that are licensed by state governments. Therefore, U.S. companies that use wood pallets or NMWP to export goods must deal with a myriad of different agencies if they intend to fumigate or chemically impregnate NMWP.
The present invention is an apparatus and system for disinfesting a large number of items by raising the temperatures of wood and wood products to a specified temperature for a specified period of time. The items are usually non-manufactured wood and/or non-manufactured wood products.
The apparatus is designed to eradicate pests from both non-manufactured wood and non-manufactured wood products. The apparatus includes an insulated or non-insulated enclosure having a first end, a second external end, a second interior end, a left wall, a right, a rigid basal structure, a primary floor, a sub-floor, an interior ceiling, an interior sub-ceiling, a means for evenly heating the interior of the enclosure and a means of recirculating the air in the enclosure in order to evenly treat the products within the enclosure.
A pair of doors allow ingress to and egress from the interior of the chamber. The doors are positioned at the first end of the chamber.
The apparatus also includes means for heating the interior of the chamber and a means for circulating the heated air. The heating means is preferably mounted at the second end of the chamber between the second interior end and the second external end.
The recirculation means includes the ceiling/subceiling assembly (referred to as a ceiling air plenum) and floor/subfloor assembly (referred to as a floor air plenum). The interior ceiling and the interior sub-ceiling, and the floor/subfloor are uniquely designed to control the flow of air within the chamber. The means for re-circulating the heated air within said interior of said chamber communicates with the heating means. The floor air plenum runs the entire length of the interior floor, and consists of perforated floor sections that form the primary floor.